Adhesive sheet

Abstract

An adhesive sheet is disclosed including a flexible substrate and an adhesive layer formed on at least one of the main surfaces of the flexible substrate. The adhesive sheet further includes a plurality of microscopic holes connecting the opposing surfaces of the sheet and being generally perpendicular to them. Such adhesive sheet is permeable by air and allows good bubble escapability when the sheet is applied to an article. Sufficient permeability of the sheet to air is achieved with microscopic size holes installed in modest areal densities, hence the appearance and functionality of the film surface are not significantly adversely impacted. One intended use of the subject invention is for tinting films used to reduce light transmission in windows for use in buildings and automobiles. In this application visual appearance of the film is paramount. Another intended application of the subject invention is for antireflective film which is applied to electronic computer displays (flat panel, cathode ray tube) to reduce unwanted ambient light reflection and to improve contrast.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] Not Applicable FEDERALLY SPONSORED RESEARCH [0002] Not Applicable SEQUENCE LISTING OR PROGRAM [0003] Not Applicable FIELD OF THE INVENTION [0004] The present invention relates to an adhesive film in a form of a sheet, strip, tape, label, tag, and the like which is perforated with microscopic holes to provide good air bubble escapability while maintaining good appearance and functionality of the film surface after being adhered to an article. BACKGROUND OF THE INVENTION [0005] Various types of adhesive films comprising a flexible substrate and an adhesive layer have been heretofore available. Such films are provided in the form of sheets, tapes, strips, labels, tags, and the like. Those films having a pressure sensitive adhesive layer generally are mounted on some type of release liner or other releasable support to protect the pressure sensitive adhesive until the film is ready to be applied to an intended article. The film is then stri...

AI Technical Summary

Benefits of technology

[0019] In each embodiment of the subject invention, the microscopic holes provide a path for air to permeate through the adhesive film of the subject invention. When the film of the subject invention is applied to a substrate, pockets of air trapped between the film and the substrate surface are relieved to outside atmosphere. As a result, formation of bubbles of trapped air is avoided. When adhered film is exposed to environment such as light and heat that cause the materials in the vicinity of adhesive bond interface generate gas, such gas is readily relieved through the microscopic holes to the atmosphere.

[0020] In many instances, most notably in consumer articles, it is desirable to remove the product label after the product has been purchased. Yet, very often the adhesive employed (usually pressure sensitive or water soluble type) adheres very well to the article and the label substrate is too weak to carry the force required to peel off the label without breaking. Softening the adhesive with suitable solvent requires great amount of time since the solvent has to penetrate the adhesive layer starting from the edge. In contrast, when the product label is fabricated in accordance with the subject invention, the solvent can readily permeate through the film substrate via microscopic holes and soften the adhesive, thereby making it possible to remove the label shortly after the solvent it applied. OBJECTS OF THE INVENTION

[0023] Yet another object of the invention is to allow for easier removal of adhesive film after it has been adhered to an adherent article.

[0024] Yet another object of the invention is to improve appearance of adhesive film adhered to an article.

[0025] Yet another object of the invention is to make easier installation of adhesive film onto an article.

Problems solved by technology

Another limitation of films with porous substrate is that when a coating or an ink for decoration is applied to the second, non-adhesive face of the substrate, it tends to close the pores of the porous substrate and initial performance cannot be obtained.

This condition is particularly problematic when a coating with sealing properties is highly desirable as the means for protecting the non-adhesive surface of the adhesive film from dust, dirt, moisture, liquids, or human touch, or when such a coating is used to improve the performance, prepare the surface for printing, or protect the print ink.

Furthermore, many desirable substrate materials including plastics and metals are not naturally porous and permeable by air.

Hence, the usefulness of permeable substrate of prior art for construction of adhesive films is very restricted.

Such sequencing is, however, difficult to achieve in practice.

Furthermore, formation of structured adhesive layer requires special equipment.

In addition, once the film is applied to an article, gasses generated at the bond interface when exposed to environment such as heat and light cannot escape and, as a result, cause bubbles and lifting.

However, this approach is not suitable for general use as it requires special preparation of adherent article surface.

Such surface preparation is costly and impractical in most situations, especially when the adherent article is a glass window or computer display.

In addition, the need for surface preparation greatly restricts the choice of adherent materials and limits the selection of sites on the surface of substrate article that are suitable for receiving adhesive film.

Images